Certain surgical procedures require retraction of soft tissue and a shunt to remove bodily fluids. Hydrocephalus, for example, is a condition caused by buildup of excess cerebrospinal fluid (CSF) in the ventricles of the brain. The increased size of the ventricles causes excess pressure on brain tissue. Symptoms may vary with age, disease progression, and individual differences, but in some cases may be fairly severe and lead to seizures, mental impairment, or death.
A common procedure to address this condition involves the formation of a surgical incision to access the excess fluid. The incision may be held open by a locking retractor tool such as a retractor device; however, conventional retractor devices have various drawbacks. Retractor devices are generally reusable and costs for each device may range anywhere from $100 to $500; with significant further costs being incurred during sterilization and maintenance. Surgical retractors are commonly made from metals such as stainless steel or anodized aluminum.
To remove the excess CSF, the procedure may further include the placement of a ventriculoperitoneal (VP) shunt to drain the excess fluid from the brain into the abdomen, blood vessels, pleura, or a number of other potential spaces in the human body. The shunt may include a ventricular catheter that is inserted into one of the brain's ventricles with a portion of the catheter remaining extracranial. This catheter is typically referred to as the proximal catheter. The extracranial end of the proximal catheter is typically attached to an adjustable valve that regulates the flow of fluid out of the ventricles. The shunt also includes a distal catheter that most often drains into the peritoneal space. This catheter is connected to the distal end of the valve, is tunneled underneath the skin, and drains into the abdomen where the fluid is then reabsorbed. During surgical placement of the proximal catheter, the intracranial pressure and/or gravity can cause this catheter to move into or out of the brain. There is also a risk of overdraining the ventricles once the proximal catheter is placed, requiring occlusion of the extracranial end of the catheter until it is connected to the inlet port of the valve.
Electromagnetic navigation guidance systems (EM systems) are often used throughout the same procedure to ensure correct placement of the proximal catheter into one of the brain's ventricles. EM systems rely upon magnetic fields to relay information to the surgeon about where in space certain surgical instruments, such as stylets inserted through the proximal catheter, are positioned in relation to the patient. Yet, EM systems often malfunction when metallic materials are used in close proximity. Thus, conventional metal retractor devices can cause a loss of catheter visualization during the most crucial parts of the procedure. Further, as described herein, the proximal catheter may migrate in or out of the brain during the procedure, or overdrain the brain's CSF if not properly secured after intracranial placement.
It is with these observations in mind, among others, that various aspects of the present disclosure were conceived and developed.